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SendMessage用法

由 怎甘沉沦 提交于 2019-12-06 21:54:04

       函数功能：该函数将指定的消息发送到一个或多个窗口。此函数为指定的窗口调用窗口程序，直到窗口程序处理完消息再返回。而函数PostMessage不 同，将一个消息寄送到一个线程的消息队列后立即返回。

函数原型：LRESULT SendMessage（HWND hWnd，UINT Msg，WPARAM wParam，LPARAM IParam）；
参数：
hWnd：其窗口程序将接收消息的窗口的句柄。如果此参数为HWND_BROADCAST，则 消息将被发送到系统中所有顶层窗口，包括无效或不可见的非自身拥有的窗口、被覆盖的窗口和弹出式窗口，但消息不被发送到子窗口。
Msg：指定被发送的消息。
wParam：指定附加的消息指定信息。
IParam：指定附加的消息指定信息。
返回值：返回值指定消息处理的结果，依赖于所发送的消息。
备注：需要用HWND_BROADCAST通信的应用程序应当使用函数 RegisterWindowMessage来为应用程序间的通信取得一个唯一的消息。
如果指定的窗口是由调用线程创建的，则窗口程序立即作为子程序调用。如果指定的窗口是由不同线 程创建的，则系统切换到该线程并调用恰当的窗口程序。线程间的消息只有在线程执行消息检索代码时才被处理。发送线程被阻塞直到接收线程处理完消息为止。
Windows CE：Windows CE不支持Windows桌面平台支持的所有消息。使用SendMesssge之前，要检查发送的消息是否被支持。
速查：Windows NT：3.1及以上版本：Windows：95及以上版本；Windows CE：1.0及以上版本；头文件：winuser.h；输入库：user32.lib；Unicode：在Windows NT环境下以Unicode和ANSI方式实现。
SendMessage函数使用实例
程序控制拉下或收起组合框的下拉列来
一般情况下，为了拉下或收起组合框的下拉列表，需要用键盘或鼠标进行操作，而有时我们希望程序 运行的某个时刻自动拉出下拉列表（比如在一些演示程序中），为了实现这个目的，我们也只有借助于SendMessage函数，方法是发一个 CB_SHOWDROPDOWN(&H14F)消息给组合框。
在发CB_SHOWDROPDOWN消息时，wParam参数决定了是拉下列表（=True 时）还是收起列表（＝False时），lParam无用（设为0）。
为说明具体的使用方法，下面提供简单的程序片段。首先在代码模块中做如下声明：
Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long,ByVal wMsg As Long，ByVal wParam As Long,lParam As Any) As Long
Const CB_SHOWDROPDOWN=&H14F
当程序中某处需要拉下组合框Combol的列表时，写如下调用语句：
SendMessage Combol.hwnd,CB_SHOWDROPDOWN,True,0
当需要收起组合框Combol的列表时，写如下语句：
SendMessage Combol.hwnd,CB_SHOWDROPDOWNN,False,0
The following are the ranges of message numbers.
Range Meaning
0 through WM_USER–1 Messages reserved for use by the system.
WM_USER through 0x7FFF Integer messages for use by private window classes.
WM_APP through 0xBFFF Messages available for use by applications.
0xC000 through 0xFFFF String messages for use by applications.
Greater than 0xFFFF Reserved by the system.
Message numbers in the first range (0 through WM_USER–1) are defined by the system. Values in this range that are not explicitly defined are reserved by the system.
Message numbers in the second range (WM_USER through 0x7FFF) can be defined and used by an application to send messages within a private window class. These values cannot be used to define messages that are meaningful throughout an application, because some predefined window classes already define values in this range. For example, predefined control classes such as BUTTON, EDIT, LISTBOX, and COMBOBOX may use these values. Messages in this range should not be sent to other applications unless the applications have been designed to exchange messages and to attach the same meaning to the message numbers.
Message numbers in the third range (0x8000 through 0xBFFF) are available for application to use as private messages. Message in this range do not conflict with system messages.
Message numbers in the fourth range (0xC000 through 0xFFFF) are defined at run time when an application calls the RegisterWindowMessage function to retrieve a message number for a string. All applications that register the same string can use the associated message number for exchanging messages. The actual message number, however, is not a constant and cannot be assumed to be the same between different sessions.
Message numbers in the fifth range (greater than 0xFFFF) are reserved by the system.
#define WM_NULL 0x0000
#define WM_CREATE 0x0001
#define WM_DESTROY 0x0002
#define WM_MOVE 0x0003
#define WM_SIZE 0x0005
#define WM_ACTIVATE 0x0006
/*
* WM_ACTIVATE state values
*/
#define WA_INACTIVE 0
#define WA_ACTIVE 1
#define WA_CLICKACTIVE 2
#define WM_SETFOCUS 0x0007
#define WM_KILLFOCUS 0x0008
#define WM_ENABLE 0x000A
#define WM_SETREDRAW 0x000B
#define WM_SETTEXT 0x000C
#define WM_GETTEXT 0x000D
#define WM_GETTEXTLENGTH 0x000E
#define WM_PAINT 0x000F
#define WM_CLOSE 0x0010
#ifndef _WIN32_WCE
#define WM_QUERYENDSESSION 0x0011
#define WM_QUERYOPEN 0x0013
#define WM_ENDSESSION 0x0016
#endif
#define WM_QUIT 0x0012
#define WM_ERASEBKGND 0x0014
#define WM_SYSCOLORCHANGE 0x0015
#define WM_SHOWWINDOW 0x0018
#define WM_WININICHANGE 0x001A
#if(WINVER >= 0x0400)
#define WM_SETTINGCHANGE WM_WININICHANGE
#endif /* WINVER >= 0x0400 */
#define WM_DEVMODECHANGE 0x001B
#define WM_ACTIVATEAPP 0x001C
#define WM_FONTCHANGE 0x001D
#define WM_TIMECHANGE 0x001E
#define WM_CANCELMODE 0x001F
#define WM_SETCURSOR 0x0020
#define WM_MOUSEACTIVATE 0x0021
#define WM_CHILDACTIVATE 0x0022
#define WM_QUEUESYNC 0x0023
#define WM_GETMINMAXINFO 0x0024
/*
* Struct pointed to by WM_GETMINMAXINFO lParam
*/
typedef struct tagMINMAXINFO {
POINT ptReserved;
POINT ptMaxSize;
POINT ptMaxPosition;
POINT ptMinTrackSize;
POINT ptMaxTrackSize;
} MINMAXINFO, *PMINMAXINFO, *LPMINMAXINFO;
#define WM_PAINTICON 0x0026
#define WM_ICONERASEBKGND 0x0027
#define WM_NEXTDLGCTL 0x0028
#define WM_SPOOLERSTATUS 0x002A
#define WM_DRAWITEM 0x002B
#define WM_MEASUREITEM 0x002C
#define WM_DELETEITEM 0x002D
#define WM_VKEYTOITEM 0x002E
#define WM_CHARTOITEM 0x002F
#define WM_SETFONT 0x0030
#define WM_GETFONT 0x0031
#define WM_SETHOTKEY 0x0032
#define WM_GETHOTKEY 0x0033
#define WM_QUERYDRAGICON 0x0037
#define WM_COMPAREITEM 0x0039
#if(WINVER >= 0x0500)
#ifndef _WIN32_WCE
#define WM_GETOBJECT 0x003D
#endif
#endif /* WINVER >= 0x0500 */
#define WM_COMPACTING 0x0041
#define WM_COMMNOTIFY 0x0044 /* no longer suported */
#define WM_WINDOWPOSCHANGING 0x0046
#define WM_WINDOWPOSCHANGED 0x0047
#define WM_POWER 0x0048
/*
* wParam for WM_POWER window message and DRV_POWER driver notification
*/
#define PWR_OK 1
#define PWR_FAIL (-1)
#define PWR_SUSPENDREQUEST 1
#define PWR_SUSPENDRESUME 2
#define PWR_CRITICALRESUME 3
#define WM_COPYDATA 0x004A
#define WM_CANCELJOURNAL 0x004B
/*
* lParam of WM_COPYDATA message points to...
*/
typedef struct tagCOPYDATASTRUCT {
ULONG_PTR dwData;
DWORD cbData;
PVOID lpData;
} COPYDATASTRUCT, *PCOPYDATASTRUCT;
#if(WINVER >= 0x0400)
typedef struct tagMDINEXTMENU
{
HMENU hmenuIn;
HMENU hmenuNext;
HWND hwndNext;
} MDINEXTMENU, * PMDINEXTMENU, FAR * LPMDINEXTMENU;
#endif /* WINVER >= 0x0400 */
#if(WINVER >= 0x0400)
#define WM_NOTIFY 0x004E
#define WM_INPUTLANGCHANGEREQUEST 0x0050
#define WM_INPUTLANGCHANGE 0x0051
#define WM_TCARD 0x0052
#define WM_HELP 0x0053
#define WM_USERCHANGED 0x0054
#define WM_NOTIFYFORMAT 0x0055
#define NFR_ANSI 1
#define NFR_UNICODE 2
#define NF_QUERY 3
#define NF_REQUERY 4
#define WM_CONTEXTMENU 0x007B
#define WM_STYLECHANGING 0x007C
#define WM_STYLECHANGED 0x007D
#define WM_DISPLAYCHANGE 0x007E
#define WM_GETICON 0x007F
#define WM_SETICON 0x0080
#endif /* WINVER >= 0x0400 */
#define WM_NCCREATE 0x0081
#define WM_NCDESTROY 0x0082
#define WM_NCCALCSIZE 0x0083
#define WM_NCHITTEST 0x0084
#define WM_NCPAINT 0x0085
#define WM_NCACTIVATE 0x0086
#define WM_GETDLGCODE 0x0087
#ifndef _WIN32_WCE
#define WM_SYNCPAINT 0x0088
#endif
#define WM_NCMOUSEMOVE 0x00A0
#define WM_NCLBUTTONDOWN 0x00A1
#define WM_NCLBUTTONUP 0x00A2
#define WM_NCLBUTTONDBLCLK 0x00A3
#define WM_NCRBUTTONDOWN 0x00A4
#define WM_NCRBUTTONUP 0x00A5
#define WM_NCRBUTTONDBLCLK 0x00A6
#define WM_NCMBUTTONDOWN 0x00A7
#define WM_NCMBUTTONUP 0x00A8
#define WM_NCMBUTTONDBLCLK 0x00A9
#if(_WIN32_WINNT >= 0x0500)
#define WM_NCXBUTTONDOWN 0x00AB
#define WM_NCXBUTTONUP 0x00AC
#define WM_NCXBUTTONDBLCLK 0x00AD
#endif /* _WIN32_WINNT >= 0x0500 */
#if(_WIN32_WINNT >= 0x0501)
#define WM_INPUT 0x00FF
#endif /* _WIN32_WINNT >= 0x0501 */
#define WM_KEYFIRST 0x0100
#define WM_KEYDOWN 0x0100
#define WM_KEYUP 0x0101
#define WM_CHAR 0x0102
#define WM_DEADCHAR 0x0103
#define WM_SYSKEYDOWN 0x0104
#define WM_SYSKEYUP 0x0105
#define WM_SYSCHAR 0x0106
#define WM_SYSDEADCHAR 0x0107
#if(_WIN32_WINNT >= 0x0501)
#define WM_UNICHAR 0x0109
#define WM_KEYLAST 0x0109
#define UNICODE_NOCHAR 0xFFFF
#else
#define WM_KEYLAST 0x0108
#endif /* _WIN32_WINNT >= 0x0501 */
#if(WINVER >= 0x0400)
#define WM_IME_STARTCOMPOSITION 0x010D
#define WM_IME_ENDCOMPOSITION 0x010E
#define WM_IME_COMPOSITION 0x010F
#define WM_IME_KEYLAST 0x010F
#endif /* WINVER >= 0x0400 */
#define WM_INITDIALOG 0x0110
#define WM_COMMAND 0x0111
#define WM_SYSCOMMAND 0x0112
#define WM_TIMER 0x0113
#define WM_HSCROLL 0x0114
#define WM_VSCROLL 0x0115
#define WM_INITMENU 0x0116
#define WM_INITMENUPOPUP 0x0117
#define WM_MENUSELECT 0x011F
#define WM_MENUCHAR 0x0120
#define WM_ENTERIDLE 0x0121
#if(WINVER >= 0x0500)
#ifndef _WIN32_WCE
#define WM_MENURBUTTONUP 0x0122
#define WM_MENUDRAG 0x0123
#define WM_MENUGETOBJECT 0x0124
#define WM_UNINITMENUPOPUP 0x0125
#define WM_MENUCOMMAND 0x0126
#ifndef _WIN32_WCE
#if(_WIN32_WINNT >= 0x0500)
#define WM_CHANGEUISTATE 0x0127
#define WM_UPDATEUISTATE 0x0128
#define WM_QUERYUISTATE 0x0129
/*
* LOWORD(wParam) values in WM_*UISTATE*
*/
#define UIS_SET 1
#define UIS_CLEAR 2
#define UIS_INITIALIZE 3
/*
* HIWORD(wParam) values in WM_*UISTATE*
*/
#define UISF_HIDEFOCUS 0x1
#define UISF_HIDEACCEL 0x2
#if(_WIN32_WINNT >= 0x0501)
#define UISF_ACTIVE 0x4
#endif /* _WIN32_WINNT >= 0x0501 */
#endif /* _WIN32_WINNT >= 0x0500 */
#endif
#endif
#endif /* WINVER >= 0x0500 */
#define WM_CTLCOLORMSGBOX 0x0132
#define WM_CTLCOLOREDIT 0x0133
#define WM_CTLCOLORLISTBOX 0x0134
#define WM_CTLCOLORBTN 0x0135
#define WM_CTLCOLORDLG 0x0136
#define WM_CTLCOLORSCROLLBAR 0x0137
#define WM_CTLCOLORSTATIC 0x0138
#define MN_GETHMENU 0x01E1
#define WM_MOUSEFIRST 0x0200
#define WM_MOUSEMOVE 0x0200
#define WM_LBUTTONDOWN 0x0201
#define WM_LBUTTONUP 0x0202
#define WM_LBUTTONDBLCLK 0x0203
#define WM_RBUTTONDOWN 0x0204
#define WM_RBUTTONUP 0x0205
#define WM_RBUTTONDBLCLK 0x0206
#define WM_MBUTTONDOWN 0x0207
#define WM_MBUTTONUP 0x0208
#define WM_MBUTTONDBLCLK 0x0209
#if (_WIN32_WINNT >= 0x0400) || (_WIN32_WINDOWS > 0x0400)
#define WM_MOUSEWHEEL 0x020A
#endif
#if (_WIN32_WINNT >= 0x0500)
#define WM_XBUTTONDOWN 0x020B
#define WM_XBUTTONUP 0x020C
#define WM_XBUTTONDBLCLK 0x020D
#endif
#if (_WIN32_WINNT >= 0x0500)
#define WM_MOUSELAST 0x020D
#elif (_WIN32_WINNT >= 0x0400) || (_WIN32_WINDOWS > 0x0400)
#define WM_MOUSELAST 0x020A
#else
#define WM_MOUSELAST 0x0209
#endif /* (_WIN32_WINNT >= 0x0500) */
#if(_WIN32_WINNT >= 0x0400)
/* Value for rolling one detent */
#define WHEEL_DELTA 120
#define GET_WHEEL_DELTA_WPARAM(wParam) ((short)HIWORD(wParam))
/* Setting to scroll one page for SPI_GET/SETWHEELSCROLLLINES */
#define WHEEL_PAGESCROLL (UINT_MAX)
#endif /* _WIN32_WINNT >= 0x0400 */
#if(_WIN32_WINNT >= 0x0500)
#define GET_KEYSTATE_WPARAM(wParam) (LOWORD(wParam))
#define GET_NCHITTEST_WPARAM(wParam) ((short)LOWORD(wParam))
#define GET_XBUTTON_WPARAM(wParam) (HIWORD(wParam))
/* XButton values are WORD flags */
#define XBUTTON1 0x0001
#define XBUTTON2 0x0002
/* Were there to be an XBUTTON3, its value would be 0x0004 */
#endif /* _WIN32_WINNT >= 0x0500 */
#define WM_PARENTNOTIFY 0x0210
#define WM_ENTERMENULOOP 0x0211
#define WM_EXITMENULOOP 0x0212
#if(WINVER >= 0x0400)
#define WM_NEXTMENU 0x0213
#define WM_SIZING 0x0214
#define WM_CAPTURECHANGED 0x0215
#define WM_MOVING 0x0216
#endif /* WINVER >= 0x0400 */
#if(WINVER >= 0x0400)
#define WM_POWERBROADCAST 0x0218
#ifndef _WIN32_WCE
#define PBT_APMQUERYSUSPEND 0x0000
#define PBT_APMQUERYSTANDBY 0x0001
#define PBT_APMQUERYSUSPENDFAILED 0x0002
#define PBT_APMQUERYSTANDBYFAILED 0x0003
#define PBT_APMSUSPEND 0x0004
#define PBT_APMSTANDBY 0x0005
#define PBT_APMRESUMECRITICAL 0x0006
#define PBT_APMRESUMESUSPEND 0x0007
#define PBT_APMRESUMESTANDBY 0x0008
#define PBTF_APMRESUMEFROMFAILURE 0x00000001
#define PBT_APMBATTERYLOW 0x0009
#define PBT_APMPOWERSTATUSCHANGE 0x000A
#define PBT_APMOEMEVENT 0x000B
#define PBT_APMRESUMEAUTOMATIC 0x0012
#endif
#endif /* WINVER >= 0x0400 */
#if(WINVER >= 0x0400)
#define WM_DEVICECHANGE 0x0219
#endif /* WINVER >= 0x0400 */
#define WM_MDICREATE 0x0220
#define WM_MDIDESTROY 0x0221
#define WM_MDIACTIVATE 0x0222
#define WM_MDIRESTORE 0x0223
#define WM_MDINEXT 0x0224
#define WM_MDIMAXIMIZE 0x0225
#define WM_MDITILE 0x0226
#define WM_MDICASCADE 0x0227
#define WM_MDIICONARRANGE 0x0228
#define WM_MDIGETACTIVE 0x0229
#define WM_MDISETMENU 0x0230
#define WM_ENTERSIZEMOVE 0x0231
#define WM_EXITSIZEMOVE 0x0232
#define WM_DROPFILES 0x0233
#define WM_MDIREFRESHMENU 0x0234
#if(WINVER >= 0x0400)
#define WM_IME_SETCONTEXT 0x0281
#define WM_IME_NOTIFY 0x0282
#define WM_IME_CONTROL 0x0283
#define WM_IME_COMPOSITIONFULL 0x0284
#define WM_IME_SELECT 0x0285
#define WM_IME_CHAR 0x0286
#endif /* WINVER >= 0x0400 */
#if(WINVER >= 0x0500)
#define WM_IME_REQUEST 0x0288
#endif /* WINVER >= 0x0500 */
#if(WINVER >= 0x0400)
#define WM_IME_KEYDOWN 0x0290
#define WM_IME_KEYUP 0x0291
#endif /* WINVER >= 0x0400 */
#if((_WIN32_WINNT >= 0x0400) || (WINVER >= 0x0500))
#define WM_MOUSEHOVER 0x02A1
#define WM_MOUSELEAVE 0x02A3
#endif
#if(WINVER >= 0x0500)
#define WM_NCMOUSEHOVER 0x02A0
#define WM_NCMOUSELEAVE 0x02A2
#endif /* WINVER >= 0x0500 */
#if(_WIN32_WINNT >= 0x0501)
#define WM_WTSSESSION_CHANGE 0x02B1
#define WM_TABLET_FIRST 0x02c0
#define WM_TABLET_LAST 0x02df
#endif /* _WIN32_WINNT >= 0x0501 */
#define WM_CUT 0x0300
#define WM_COPY 0x0301
#define WM_PASTE 0x0302
#define WM_CLEAR 0x0303
#define WM_UNDO 0x0304
#define WM_RENDERFORMAT 0x0305
#define WM_RENDERALLFORMATS 0x0306
#define WM_DESTROYCLIPBOARD 0x0307
#define WM_DRAWCLIPBOARD 0x0308
#define WM_PAINTCLIPBOARD 0x0309
#define WM_VSCROLLCLIPBOARD 0x030A
#define WM_SIZECLIPBOARD 0x030B
#define WM_ASKCBFORMATNAME 0x030C
#define WM_CHANGECBCHAIN 0x030D
#define WM_HSCROLLCLIPBOARD 0x030E
#define WM_QUERYNEWPALETTE 0x030F
#define WM_PALETTEISCHANGING 0x0310
#define WM_PALETTECHANGED 0x0311
#define WM_HOTKEY 0x0312
#if(WINVER >= 0x0400)
#define WM_PRINT 0x0317
#define WM_PRINTCLIENT 0x0318
#endif /* WINVER >= 0x0400 */
#if(_WIN32_WINNT >= 0x0500)
#define WM_APPCOMMAND 0x0319
#endif /* _WIN32_WINNT >= 0x0500 */
#if(_WIN32_WINNT >= 0x0501)
#define WM_THEMECHANGED 0x031A
#endif /* _WIN32_WINNT >= 0x0501 */
#if(WINVER >= 0x0400)
#define WM_HANDHELDFIRST 0x0358
#define WM_HANDHELDLAST 0x035F
#define WM_AFXFIRST 0x0360
#define WM_AFXLAST 0x037F
#endif /* WINVER >= 0x0400 */
#define WM_PENWINFIRST 0x0380
#define WM_PENWINLAST 0x038F

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